Regulating device for dampers for elastic vehicle suspensions



Nov. 27, 1934. H. PIEPER l 1,982,398

REGULATINGDEVICE FOR DAMPERS FOR ELASTIC VEHICLE SUSPENSIONS Filed oct; 13, 1932 ZZ Patented Nov. 27, 1934 REGULATING DEVICE FOR DAMPERs Fon ELAsrIo VEHICLE sUsPENsIoNs Henri Pieper., Brussels, Belgium Application October 13, 1932, Serial No. 637,629

` In'Bellgiurn October 17, 1931 62 Claims.

- Theinvention relates to a devicefordarnping the deformations of the elastic suspension lof vehicles. f

Pneumatic and hydraulic devices are already` known in which the damping of the oscillations of vehicle suspensions is obtained by means of two elements forming a piston and cylinder and the one of which, for instance thepis'ton, is conf' nected to the one member of the suspension, for `10|.. instance to the vehicle framejwhilst the other element, for instance the cylinder, is attachedto the second member, of the'suspensin `i.` eftothe vehicle axle.

Eurthermore suspension devices exist in which the, tightness of,I the suspension and'pljticularly the brakingaction of the` shock-damper depends on4 the vehicle speed or. is controllable by hand.

else. 'Pneumaiiefdempine errergements areal? readytin use in which the energy fof" the oscillatiens et the eusrerises. is utilizedfer .Iiieiiirilg the tightness Qfe1 deriee-eemp1isingesten, etliilf der and'airp'ad independence onthe `amplitude oi?.A

the-eseilletiPnS-f i A All. these devises ere defective.. because-they f1.0 Zimt simultaneously. "aad, euiemetieellr .adept themselves te thevehiele sneedA and te. the State of the road or they do not act inconforinity to` the, frequensr and amplitude ofthe eee'illtieiis ansiA de netfellewfin a rapid. @ed Properties@ 39. mannerlthe variations of the state of-Y the road-or the, passefeesef. the .vehicle Wheels fmeuehheles er other, defeets @fthe read The inrentieahesfer en. Obieei t9 eroi@ these drawbacks and` to produceA an automaticyvariaf tion of the. tightness ofa vehiclel suspension inf prepertionte vthe Stroke. effectedby the 011e Slispeusen memberreletively te the other iein proportion to the frequency and` amplitude ofthe oscillations or deformations ofthe suspension-l andv thereby to the vehicle speed as well as to the road state, and to the vehicle'load so as to, guarf theme Suspenden member irelatively te the ether. The lpiston. ef the Pump 1111er 'be eermeeted for instanceto the frame of thevehicle andthe pump cylinder to the.. vehicle axle andthereceiverniay it leengstituiedeleabr eylmseif ses @Pisten and.

the displacement of thispiston produces an increase of theitightn'ess ofthe suspensior'i;`

The receiver cylinder is provided with an out.- let orice of small lsection which.' may bevari-f. able, preferablyr in dependence on theweight. "olf they vehicle frame. The"cross-sectional"area'df this orice has such small dimensionsin respect. to the cross-'sectional area of tlejpump cylinder', that"v the pressure stroke of the piiiiip piston" charges the receiver butthat thescapllfof liquidf through the small outlet oriiicevof'th' receiver cannot Vrapidly counteract .tliisaction of' thefpresf' sure stroke of the pump piston. Consequen yithe.y pressure in the receiver cylinder depends i n'tlie liquid supply furnished by the pump in a'bgiven 79,. time 'and this liquid supply is' the larger "as theA state of the lroad is more defective and asthe ver' mele rjuns more rapidly; Whilstin the `known hydraulic damping. de# vices combined to vehicle suspensions the pressure' of the vliquid varying' in conformity tothe iiexingsfo'fthe suspension springs oscillatesbetween the value zeroand'another certain value dpendf' ing onthestate of the road, according'to the'inl-4 vention'a certain intermediate *pressure ismain 30, tained in the receiving cylinder as long asv the vehicle axles are subjected to vertical displace-nl ments.` wThis action ofthe receiver cylinder'augments the' friction in the case of dam'pingfdevices. workingby friction and stiifens or tightens the` 3,5. springs of the suspension andv thereby prodcesan automatic regulation of anydamping device.-A "The utilizing of the receiver pressurefor stiffening" thelsusp'ension'may be effected by having. the "receiver piston act upon auxiliary "plate: 9.9. springsfor upon the controlling member 'of the shock`-da`rnpers for instance the 'damping' nut` of the shock-dampers Working by friction or upon` the yclosing member controlling the passage ofthe nquid in hydraulic shock-campers." The 9.5 receiver'pistonis connected to a return spring, for instance a helical spring, uor tothe auxiliary plate springs so as to produce a Vslow escape'of the incompressibleliquid through the outlet orificeof nsmall-section and to assure the 'highest 1,00 degree of elasticity of the suspension'l until, eventually, a new working of thepusmp tends. to augmentA the stilness ofthe suspension. "On a given road and forever'y ,vehicle speed there rapidly vestablished in the'receiver ua 1,05 working pressure havingv the same valueas long as. the" state 'of the' road and. the speed' offth'e vehicle remain the same. Consequently the. stiffness or tightness of the suspension'iniiuenced by this pressure is automaticallyadapted tov "lf 1 10 road state and the vehicle speed. The piston of the receiver upon which this pressure acts permanently brakes more or less the springs of the damper so as to diminish the oscillations of the vehicle axle.

According to the invention, the stiffness of the suspension of the vehicle may be regulated also in dependence on the load of the vehicle by using the variations of the flexings of the suspension device for acting, for instance by means of levers upon a valve controlling the outlet orifice of the receiver cylinder. Furthermore, in the case of a self-propelling vehicle a single regulating device according to the invention may be employed and the receiver piston of this device may be connected to each of the four shock-dampers of the vehicle or there may be arranged upon the vehicle two or four separate devices constructed according to the invention, each acting upon one ofthe axles or of the extremities of the axles.

The accompanying drawing shows by way of example several embodiments of the invention. Figure 1 is a schematic representation of the whole damping and regulating device according to the invention. Figure 2 illustrates the application of the invention to a self-propelling vehicle the suspension springs of which are combined to auxiliary plate springs. Figure 3 shows anembocliment of the invention in the case of a vehicle suspension provided with a shock-damper working by friction. The corresponding elements of the three figures are designated by the saine numerals.

Figure 1 shows the two parts of an elastic vehiclesuspension, namely the frame 2 and the laminated leaf spring 3. The spring 3 carries the axle (not shown) of a self-propelling vehicle. The piston 4 of a pump is articulated to the A frame 2 whilst the pump cylinder 5 is attached to the laminated spring 3 and followsthe displacements of this spring. A reservoir 6 contains an incompressible liquid, for instance water or oil and is in communication with the pump cylinder 5 by means of the pipe 7 containing an automatic valve 7 opening towards the cylinder 5.

' A piston 8 and a cylinder 8 form a receiver which is connected to the pump cylinder 5 by means of a pipe 9 containing an automatic valve 9 opening towards the receiver cylinder 8'.' A pipe 10 of a relatively small diameter connects the cylinder 8' with the reservoir 6 open to the atmosphere. The effective area of this throttlel.. pipe 10` may be regulated for instance by means` of an adjustable pin 11 carrying a cone valve controlling the entrance opening of the pipe 10 at the bottom of the reservoir 6.

The pin 11 may be adjusted by hand before the start of the vehicle in conformity to they load of the vehicle in order to regulate the working of the device according to the load.l Also an automatic adjusting of the pin 1l may be effected by controlling the movement of the pinv 11 by means of gearing 20, 21, 22 and 23, whichl is influenced and moved by the variations of the exure of the vehicle suspension. The rack 20 is connected to the spring 3 and actuates the toothed wheel 2l which transmits its rotation by means of the conicalV wheel 22 to the conical r ally into the lsquare tube 24 so that the valve cone fixed to the lower end of the pin 11 can execute also a relative axial movement with respect to the tube 24 when being rotated by this tube. The rod 8" fixed to the receiver piston 8 is articulated to a shock-damper 12 not shown in detail, to auxiliary springs or to a similar` device so as to vary and increase the stiffness of the suspension when displaced toward the right hand.

Figure 2'shows the application of the invention to the case where the vehicle suspension comprises, besides the laminated spring 3, also an auxiliary leaf spring 32 to which is connected therod 8 ofthe receiver piston 8. The cyliny ders 8 and and the reservoir 6 are carried by the spring 3 to which they are attached whilst the pump piston 4 is articulated to the vehicle frame 2.

According to Figure 3 the rod 8" of the receiver piston 8 is articulated by means of a lever 13 to the clamping nut 13 of a shockdamper 12a, working by friction and being of any known construction. The cylinders 5 and 8 and the reservoir 6 are connected as in the case of Figure 2 to the suspension .spring 3 and the pump piston 4 is articulated to the vehicle frame 2. A receptacle l5 containing air may be connected as shown in dotted lines in Figure 3 and l, to thev receiver cylinder 8 in order to obtain a regular working of the whole device by means of this air-chamber.

The operation of the devices shown by Figures 1 to 3 is as follows: The pump piston 4 draws in, during each suction stroke, incompressible liquid from the reservoir 6 into the pump cylinico ros

der 5 through the pipe '7 and the valve 7 and it forces, during each pressure stroke, liquid from the pump cylinder 5 into the receiver cylinder 8 through the pipe 9 and the valve 9' and the quantity of liquid pumped into theA receiver cylinder 8 is proportional to the amplitude of the dis-A placements of the suspension spring 3. The re` ceiver piston 8 is displaced tothe right hand to an extent corresponding to this pumping action against the action of va return spring, for instance of the-helical spring 14 of Figure 1 and 3 or of the.`

auxiliary leaf spring 32 of Figure 2, whereby an increase of the tightness of -the suspension is obtained.

In consequence of the small diameter of the escape pipe 10 connecting cylinderA 8 and reservoir 6,the return spring 14 or 32 can replace but relatively slowly the receiver piston 8 into a position for which the tightness of the suspension is less and this takes place when the pumping action of thel piston 4 decreases or ceases.

After one stroke or a plurality of strokes of the pump piston 4, therefore, there is established in the receiver cylinder 8 a working pressure which depends on the road state and the vehicle speed i. e. the output of the pump 4, 5.

In this way, the tightness of the vehicle suspension is automatically adapted by the actionv of the receiver piston 8 to the road state and the vehicle speed whereby a favorable Working of the suspension is assured at each ,vehicle speed V and upon each road. At the same time vthe further advantage is obtained thatthe regulating device, according to the invention, provides also an automatic correction of a defective Working of the shock-damperswhich is produced by a. variation of the coefficient of friction in the case of mechanical shock-dampers or by a variation of the coefficient of viscosity in the case of hydraulic shock-dampers.

The invention maybe embodied in detail also in a manner differing from that of the examples shown in the accompanying drawing in order to be adapted to the particularities of the case of application, without departing from the spirit and scope of the invention or sacrificing any of its advantages in the meaning of the appended claims.

I claim:

1. A regulating device for dampers for elastic vehicle suspensions comprising in combination a pump having its piston connected to the vehicle frame and its cylinder to the vehicle axle, a reservoir, an'incompressible liquid contained in said reservoir, a conduit connecting said reservoir to said pump cylinder, a check valve arranged in said conduit and opening towards said pump cylinder, a receiver constituted by a cylinder and a piston, a conduit connecting said receiver cylinder to said pump cylinder, a valve inserted in said latter conduit and opening towards said receiver cylinder, another conduit connecting said receiver cylinder and said reservoir and having a diameter relatively small with respect to the diameter of said conduit connecting said receiver to said pump cylinder, a return spring acting upon said receiver piston and means adapted to connect said receiver piston to said vehicle suspension to increase its resistance when displaced by the action of said pump.

2. A regulating device as set forth in claim 1 characterized by an adjustable pin and a cone attached to the one end ofsaid pin, said pin and said cone being arranged in such relation to the conduit of small diameter that ow through the conduit can be varied by adjusting said pin.

3. A regulating device as set forth in claim 1 characterized by having a pin and cone valve regulating the flow through the conduit of small diameter and further characterized by means for adjusting the pin carrying the cone by the action of the variations of the deflection of the vehicle suspension in dependence on the load of the vehicle.

4. A regulating device as set forth in claim 1 characterized by the return spring being formed by an auxiliary leaf spring combined to the suspension spring and acting upon the receiver piston.

5. A regulating device as set forth in claim 1 characterized by the fact that the communication between the receiver cylinder and the reservoir containing the incompressible liquid is established by the aid of the pump cylinder the piston of which is attached to the one of the two members of the vehicle suspension whilst the receiver cylinder, the pump cylinder and the reservoir are carried by the other member of the suspension.

6. A regulating device as set forth in claim 1 in which a shock-damper is combined with the vehicle suspension characterized by the fact that the receiver piston is articulated to the controlling member of said shock-damper so as to increase the resistance of the shock-damper when said piston is displaced by the action of the Dump.

HENRI PIEPER. 

